WO2009055315A2

WO2009055315A2 - A variable orifice fuel injector with a single needle valve and engines using the same

Info

Publication number: WO2009055315A2
Application number: PCT/US2008/080401
Authority: WO
Inventors: Deyang Hou
Original assignee: Deyang Hou
Priority date: 2007-10-21
Filing date: 2008-10-18
Publication date: 2009-04-30
Also published as: WO2009055315A3

Abstract

The invention disclosed a fuel injector with variable orifice and a single needle valve, which is a fuel injection device for internal combustion engines, either diesel or gasoline engines. A variable orifice fuel injector, which is a high-accuracy couple of components comprising: (i) a nozzle body, which has fuel passages, which has inner cylindrical spaces for receiving a movable part, (ii) a needle valve, which has a converging- diverging conical head wherein has plural number of small channels to communicate fuels between two spaces composed by the said nozzle body and needle valve itself, which is movable back and forth and received in said nozzle body, wherein said needle valve is at a biased closing position or an opening position defined by driving means, (iii) a variable orifice on the said nozzle body comprising at least two rows of fuel channels with different diameters and different centerline angles between their center lines and the centerline of the said needle valve, with smaller diameter channels has smaller centerline angles and larger diameter channels with larger centerline angles, (iv) the said variable orifices was formed by the said moving needle valve and said nozzle body such that the said orifice fuel channels can be opened and closed selectively and continuously with different inlet areas, wherein has means of discharging fuel in variable sprays with different spray angles and penetrations through said variable orifice by lifting said needle valve at different magnitudes.

Description

A VARIABLE ORIFICE FUEL INJECTOR WITH A SINGLE NEEDLE VALVE AND

ENGINES USING THE SAME

DESCRIPTION

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 60981501, filed on October 21, 2007.

BACKGROUND OF THE INVENTION

1. Field of the Invention - The invention relates to a micro-variable multihole orifice (MVMO) fuel injector with a single needle valve, and particularly to a fuel injector for a direct injection internal combustion engine, which can be either a spark-ignition gasoline engine or a compression-ignition diesel engine. The current filing is focused on the nozzle part of the fuel injector.

2. Description of the Related Art - The combustion process in a conventional direct injection Diesel engine is characterized by diffusion combustion with a multi-hole fuel injector. Due to its intrinsic non-homogeneous characteristics of fuel-air mixture formation, it is often contradictory to simultaneously reduce soot and NOx formation in a conventional diesel engine. Over last two decades, significant progress has been made for Diesel engine combustion (United States Patents No. 4,779,587, 6,230,683), but further reducing emissions from Diesel engines to comply upcoming emission legislations still remains a challenge. Progress has been made in recent years for research of Homogeneous-Charge Compression-Ignition (HCCI) combustion engines. However, many issues remain to be solved to have a practical approach to control the ignition timing, the duration of combustion, the rate of combustion for HCCI engine for various load conditions. Current engine control strategies, such as US Patent No. 6,230,683, are effective but very complex and will increase the cost for applications. It seems more a viable solution to operate engine in a mixed-mode, or in HCCI mode or PCCI mode at low to medium loads, and in conventional spray combustion mode at high loads for the near future, or even operate the engine in a dual-mode combustion within a same power cycle, regardless loads. It would be desirable to design a fuel injector which is suitable for this type of mixed-mode combustion, at least to provide most features desired by optimal engine combustion.

To improve combustion at the full load range, fine atomization with accurate control of fuel doses and timing is needed. A well-known current art for improving atomization is to increase the number of holes of nozzles and decrease the diameter of nozzle holes, and use piezo actuators and high common rail pressure (United States Patents 6,726,121, 6,557,779), such as BOSCH' s piezo-injector with coaxial- vario-nozzle (Roger Busch, Advanced Diesel Common Rail Injection System for Future Emission Legislation, Diesel Engine Emission Reduction Conference, Aug., 2004, Coronado, California). Such an approach, while it's effective for improving atomization and combustion, it does, at the same time, mandate a very complex structure and a much higher rail pressure, thus increase the power needed for fuel pump and manufacture cost of fuel systems, and increase the potential risks of fuel leaking.

3. Objectives and Advantages - It is the objective of this invention to give a injector suitable for mixed-mode HCCI-conventional or PCCI-conventional combustion, with simple and robust structure and low cost. The said MVMO injector can generate spray patterns to meet the needs for variable spray penetration, Sauter Mean Diameter, and spray patterns for different engine operating conditions. The MVMO can provide an optimized spray pattern, including variable spray angles, to minimize wall- wetting and oil dilution related to early and post injections. Thus, MVMO design provides significant adaptive capability for different operating loads to optimize engine combustion. MVMO is a key enabler to extend premix combustion or PCCI/HCCI operating maps. The MVMO provides a continuously variable spray pattern to fit in the need for combustion optimization for a broad load, speed, and injection timing ranges. It provides significant potential for a high efficiency clean engine with flexible fuel. The MVMO injector provides significant edges for transient emission reduction. Mixture formation is most critical for auto engine combustion. While the engine industries have put great efforts for HCCI and/or PCCI combustion, the conventional multi-hole injector limits the operation ranges of HCCI and PCCI. The major reasons are due to the fixed injection angle and dense jet nature of conventional sprays. Since current HCCI or PCCI can only operate in low to medium loads in practical applications, conventional fixed- area nozzle designs have to be compromised for low and high loads. A fixed larger included spray angle for high loads will bring severe wall wetting issues for early injections dictated by HCCI/PCCI mixture formation needs. A fixed narrow included spray angle optimized for premixing will generate more soot for high loads. Thus, a variable spray angle and penetration are well positioned to solve this contradiction between the needs for different injection timings. The design of MVMO injector has solved this wall- wetting issue through providing a variable spray included angle, which is smaller for early injection and becomes larger for later injection, and a variable spray pattern, which is soft small sprays for early injection with smaller penetration, and becomes multi-jet lager sprays for later injection with higher penetration strength. MVMO also provides adaptive sprays for different back pressure due to different supercharging needs for different loads, thus potentially enable high power density. Given many desirable features for combustion, said MVMO fuel injector also has a relatively simple structure, instead of a complex structure with two needle valves, it uses a single needle valve to generate variable sprays through novel orifice design. It can save manufacturing cost. Said fuel injector provides a key device for meeting the current and future engine emission regulations.

SUMMARY OF THE INVENTION

The invention disclosed a fuel injector with variable orifice and a single needle valve, which is a fuel injection device for internal combustion engines, either diesel or gasoline engines. A variable orifice fuel injector, which is a high-accuracy couple of components comprising: (i) a nozzle body, which has fuel passages, which has inner cylindrical spaces for receiving a movable part, (ii) a needle valve, which has a converging- diverging conical head wherein has plural number of small channels to communicate fuels between two spaces composed by the said nozzle body and said needle valve itself, which is movable back and forth and received in said nozzle body, wherein said needle valve is at a biased closing position or an opening position defined by driving means, (iii) a variable orifice on the said nozzle body comprising at least two rows of fuel channels with different diameters and different angles between their center lines and the centerline of the said needle valve, with smaller diameter channels has smaller angles and larger diameter channels with larger angles, (iv) the said variable orifices was formed by the said moving needle valve and said nozzle body such that the said orifice fuel channels can be opened and closed selectively and continuously with different combined inlet areas, wherein has means of discharging fuel in variable sprays with different spray angles and penetrations through said variable orifice by lifting said needle valve at different magnitudes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary sectional view of a first exemplary embodiment of Nozzle Body Embodiment I. (a) side view; (b) cross-section view; (c) bottom view;

FIG. 2 is a fragmentary sectional view of second exemplary embodiment of Nozzle Body Embodiment II. (a) side view; (b) cross-section view; (c) bottom view;

FIG. 3 is a fragmentary sectional view of a third exemplary embodiment of Nozzle Body Embodiment III. (a) side view; (b) cross-section view; (c) bottom view;

FIG. 4 is a fragmentary sectional view of an exemplary embodiment of Needle Structure Embodiment I. (a) side view; (b) cross-section view; (c) bottom view;

FIG. 5 is a fragmentary sectional view of a second exemplary embodiment of Needle Structure Embodiment II. (a) side view; (b) cross-section view; (c) bottom view;

FIG. 6 is a fragmentary sectional view of the Variable Orifice Opening Process.

FIG. 7 is an illustration of the variable orifice assembly. 10 - nozzle body, 20 - needle valve, 11 - large fuel channels, 122 - small fuel channels, 121 - composite fuel channels, 21- communication fuel channels in needle head, Vl - volume above sealing surface, V2 - volume below sealing surface and above needle head, V3 - volume below needle head.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Figure 1 ~ Figure 3 demonstrate three nozzle body implementations.

In Figure 1, wherein the nozzle body has a plural number of fuel channels, preferably 12- 18, to discharge fuel, wherein the fuel channels are distributed on at least two rows with different diameters, preferably 60-240 micron meters, and different angles, preferably between 30-70 degree (or 60-140 included spray angles) between its centerlines and centerline of the needle valve, wherein the inlets of the fuel channels are distributed with two smaller outlets sit above and between two larger inlets, wherein the outlets of the fuel channels are distributed with two smaller outlets sit bellow and between two larger outlets, which resembling a 'parents-children' distribution.

In Figure 2, wherein the nozzle body has a plural number of fuel channels, preferably 12- 18, to discharge fuel, wherein the fuel channels are distributed on at least two rows with different diameters, preferably 60-240 micron meters, and different angles, preferably between 30-70 degree (or 60-140 included spray angles) between its centerlines and centerline of the needle valve, wherein the inlets of the fuel channels are distributed with two smaller outlets sit above and between two larger inlets, wherein the smaller diameter fuel channels are 'composite channels' with at least two different diameters in their axial direction, which provide means for easy manufactures and reducing the length to diameter ratio of the small fuel channels.

In Figure 3, wherein the nozzle body has a plural number of fuel channels, preferably 12- 18, to discharge fuel, wherein the fuel channels are distributed on at least two rows with different diameters, preferably 60-240 micron meters, and different angles, preferably between 30-70 degree (or 60-140 included spray angles) between its centerlines and centerline of the needle valve, wherein the inlets of the fuel channels are distributed with one smaller inlet sits above and between two larger inlets, wherein the outlets of the fuel channels are distributed with one smaller outlet sits bellow and between two larger outlets, which resembling a special 'alternate' distribution, thus have means to reverse the altitude of the inlets and outlets of the fuel channels with different diameters.

In Figure 4, A fuel injector of claim 1, wherein the communication channels have a 'tree structure'. In Figure 5, A fuel injector of claim 1, wherein the communication channels have a 'cable cross-section' bottom view. With communication channel angle c approximately in the range of 20 to 60 degree, and communication channel diameter in the range of 0.2 mm to 0.5 mm;

Figure 6 illustrates the operation process of the said variable orifice. When needle lift is zero or at seating position, no fuel come out of neither small or large channels. When needle is lifted a small LO but less than a predefined Ll, fuel will come out from the small channels only. When needle is fully lifted at Ll, where the small channels are closed but the large channels are just partially open, fuel will come out from large channels only. When needle is further lifted to L2, large channels are fully open, fuel will come out from large channels only. In Figure 6, where in a variable orifice fuel injector as in claim 8, including features of claim 1, 6 , and 7, which is a high-accuracy couple of components comprising: (i) a nozzle body, which has fuel passages, which has inner cylindrical spaces for receiving a movable part, (ii) a needle valve, which has a converging-diverging conical head which has plural number of channels to communicate fuels between two spaces separated by the needle valve head itself, which is movable back and forth and received in said nozzle body, wherein said needle valve is at a biased closing position or an opening position defined by driving means, (iii) a variable orifice on the said nozzle body comprising by at least two rows of fuel channels with different diameters and different included angles, with smaller diameter channels have smaller included angles and larger diameter channels with larger included angles, with smaller channels connected to the upper fuel sac volume and larger channels connected to the lower fuel sac volume, (iv) the said variable orifices was formed by the said moving needle valve and said nozzle body such that the said orifice fuel channels can be opened and closed selectively and continuously to increase or decrease different combined inlet areas, wherein have means of discharging fuel in variable sprays of multi-jet shapes with different spray angles and penetrations through said variable orifice by lifting said needle valve at different magnitudes, (v) the ratio of the diameters of said smaller fuel channels and larger fuel channel on the orifice is between 0.3-0.7, preferably 0.5, (vi) the included angle of the said large fuel channels is between 120-150 degree, preferably 130-140, the included angle of small channel is between 60-120 degree, preferably 60-100 degree; (vii) the diameter of the small fuel channels are approximately between 80-120 micron meter, preferably 80-100 micron, the diameter of the large fuel channels are approximately between 100-240 micron meter, preferably 120-180 micron meter, (viii) the diameter of the guiding needle head of the said needle valve is between 0.8-2 mm, preferably 1.0-1.4 mm, (vi) the number of the fuel channels pass through the needle head is between 1-6, preferably 4-6; (ix) the said needle valve is a single moving body.

Claims

What is claimed is:

1. A variable orifice fuel injector, which is a high-accuracy couple of components comprising: (i) a nozzle body, which has fuel passages, which has inner cylindrical spaces for receiving a movable part, (ii) a needle valve, which has a converging- diverging conical head wherein has plural number of small channels to communicate fuels between two spaces composed by the said nozzle body and said needle valve itself, which is movable back and forth and received in said nozzle body, wherein said needle valve is at a biased closing position or an opening position defined by driving means, (iii) a variable orifice on the said nozzle body comprising at least two rows of fuel channels with different diameters and different angles between their center lines and the centerline of the said needle valve, with smaller diameter channels has smaller angles and larger diameter channels with larger angles, (iv) the said variable orifices was formed by the said moving needle valve and said nozzle body such that the said orifice fuel channels can be opened and closed selectively and continuously with different combined inlet areas, wherein has means of discharging fuel in variable sprays with different spray angles and penetrations through said variable orifice by lifting said needle valve at different magnitudes.

2. A fuel injector of claim 1, wherein the nozzle body has a plural number of fuel channels to discharge fuel, wherein the fuel channels are distributed on at least two rows with different diameters and angles between its centerlines and centerline of the needle valve, wherein the inlets of the fuel channels are distributed with two smaller outlets sit above and between two larger inlets, wherein the outlets of the fuel channels are distributed with two smaller outlets sit bellow and between two larger outlets, which resembling a 'parents-children' distribution.

3. A fuel injector of claim 1, wherein the nozzle body has a plural number of fuel channels to discharge fuel, wherein the fuel channels are distributed on at least two rows with different diameters and angles between its centerlines and centerline of the needle valve, wherein the inlets of the fuel channels are distributed with one smaller outlet sits above and between two larger inlets, wherein the outlet of the fuel channels are distributed with one smaller outlet sits bellow and between two larger outlets, which resembling a special 'alternate' distribution, thus have means to reverse the altitude of the inlets and outlets of the fuel channels with different diameters.

4. A fuel injector of claim 1, wherein the nozzle body has a plural number of fuel channels to discharge fuel, wherein the fuel channels are distributed on at least two rows with different diameters and angles between its centerlines and centerline of the needle valve, wherein the smaller diameter fuel channels are 'composite channels' with at least two different diameters in their axial direction, which provide means for easy manufactures and reducing the length to diameter ratio of the small fuel channels.

5. A fuel injector of claim 1, wherein the needle valve has a converging-diverging conical head which has plural number of channels to communicate fuels between two spaces composed by the said nozzle body and the said needle valve itself, wherein the bottom view of the needle valve resembling a cross section of a cable line.

6. A variable orifice fuel injector, which is a high-accuracy couple of components comprising: (i) a nozzle body, which has fuel passages, which has inner cylindrical spaces for receiving a movable part, (ii) a needle valve, which has a converging- diverging conical head which has plural number of small channels to communicate fuels between two spaces composed by the said nozzle body and the said needle valve itself, which is movable back and forth and received in said nozzle body, wherein said needle valve is at a biased closing position or an opening position defined by driving means, (iii) a variable orifice on the said nozzle body comprising at least two rows of fuel channels with different diameters and different angles between their centerlines and the centerline of the needle valve, with smaller diameter channels has smaller angles and larger diameter channels with larger angles, with smaller channels connected to the upper fuel sac volume and larger channels connected to the lower fuel sac volume, (iv) the said variable orifices was formed by the said moving needle valve and said nozzle body such that the said fuel channel inlets can be opened and closed selectively and continuously to increase or decrease combined channel inlet areas, wherein it has means of discharging fuel in variable sprays of multi-jet shapes with different spray angles and penetrations through said variable orifice by lifting said needle valve at different magnitudes, (v) the ratio of the diameters of said smaller fuel channels and larger fuel channel on the orifice is between 0.3-0.7, (vi) the centerline angle of the said large fuel channels is between 120-150 degree, the centerline angle of small channels is between 60-120 degree; (vii) the diameter of the small fuel channels are approximately between 50-120 micron meter, the diameter of the large fuel channels are approximately between 100-240 micron meter.

7. A variable orifice fuel injector, which is a high-accuracy couple of components comprising: (i) a nozzle body, which has fuel passages, which has inner cylindrical spaces for receiving a movable part, (ii) a needle valve, which has a converging- diverging conical head which has plural number of small channels to communicate fuels between two spaces composed by the said nozzle body and the needle valve itself, which is movable back and forth and received in said nozzle body, wherein said needle valve is at a biased closing position or an opening position defined by driving means, (iii) a variable orifice on the said nozzle body comprising at least two rows of fuel channels with different diameters and different angles between their centerlines and the centerline of the said needle valve, with smaller diameter channels has smaller angles and larger diameter channels with larger angles, (iv) the said variable orifices was formed by the said moving needle valve and said nozzle body such that the said fuel channel inlets can be opened and closed selectively and continuously with different combined inlet areas, wherein it has means of discharging fuel in variable sprays of multi-jet shapes with different spray angles and penetrations through said variable orifice by lifting said needle valve at different magnitudes, (v) the diameter of the guiding needle head of the said needle valve is between 0.8-2 mm, (vi) the number of the fuel channels pass through the said needle head is between 1-6; (vii) the said needle valve is a single body with same motion.

8. A variable orifice fuel injector, which is a high-accuracy couple of components comprising a nozzle body as defined in claim 6, and a needle valve as defined in claim 7.

9. An internal combustion engine, can be either spark ignition or compression ignition or their combination, wherein has means to provide a mixed-mode HCCI- conventional or PCCI-conventional combustion by using the fuel injector in claim 1.

10. A fuel injector of claim 1, wherein the channel sizes for the smaller channels and larger channels become same.